When you try to run a Microsoft SharePoint 2013 workflow in Microsoft SharePoint Online, you receive an error message that resembles the following:
Retrying last request. Next attempt scheduled after Date/Time. Details of last request: HTTP Unauthorized to SharePointSiteCollectionURL ...Correlation Id: CorrelationId Instance Id: InstanceId.
Currently, the SharePoint 2013 Workflow Service does not provide Trusted Network policy support, such as for IP address restrictions. When the Workflow 2013 makes a call to the Azure Workflow Service, the response is returned to SharePoint Online from a different IP address. This behavior triggers an access request restriction and causes the "unauthorized" error message that is mentioned in the "Symptoms" section.
To resolve this issue, follow these steps:
Go to your tenant administration:
Locate Access Control.
Under the Control access based on network location setting, clear the Only allow access from specific IP address locations check box.
NOTE: Currently, there are no persistent lists of the Office 365 Azure Workflow Service endpoints to add to the Allow list.
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